.With these products, have you guys done any calibrations on the devices.I bought a popular clamp-on device and found that it's accuracy left a great deal to be desired.

One of the best buys that I have made is a Plug-Pack Watt-Meter device from ALDI (Only sold when on special)( One is permanently connected to the heat-pump )This device can be used with any appliance, and has the benefit of a 7 day bar-graph, providing instant recognition of problems.. eg.. One fridge I HAD , was drawing 7KwH a day, and another 2KwH.That inefficient fridge was quickly replaced, and I estimated that it's cost would be recouped in three years of electricity savings. At $15, the meter was a very good buy for actually monitoring ANY device..

I have a 15amp PowerMate for monitoring individual devices, and that has been tested against my (good quality) multimeter, and also against a Country Energy "certified" multimeter. It is well within the level of accuracy required for such a device.

The Wattson, on the other hand, I have never tried to check. To me the absolute degree of accuracy in such a device is not relevant. It makes it very obvious when more than "background" consumption is happening, and is accurate enough to give information on usage patterns etc. In the overall scheme of things, whether the entire house is drawing 500watts or 550watts is not vital knowledge to me, but to know that a pump is stuck on (+750watts) or all the upstairs lights have been left on when the kids have gone out is far more useful.

The advertising blurb for the Wattson says that because the main unit is rechargeable it can be used "handheld" as individual appliances are switched on and off to check their consumption. The reality is that most appliances do not use a constant amount of power, so such short term testing is a waste of time even if the change can be isolated to one appliance - remembering that the clamps are in the meter/fuse box so any other change in the house (fridge thermostat etc.) can easily swamp the change made by switching off another appliance.

That is why I use the PowerMate for such tasks - it can be left connected to an appliance and will measure not only the instantaneous consumption, but also total consumption over time, maximum power draw etc. Such information is far more useful than knowing that the fridge draws 400W, because it may only draw 400W for a few minutes and then draw nothing for hours...

I downloaded Powometer to have a look. In reality I don't think it's "better" than Holmes, it's just different. It has a few neat features, like the ability to add alternative electricity retailers and do "what if" analysis on switching between tariffs. It also has real time graphing function. However it does not support TOU rates, only the UK style "Economy 7" rate and a consumption driven rate. Those people on 3 way TOU meters that regard the entire weekend as "off peak" cannot get accurate financial results from this software. It also does not seem to have any ability to make changes to the Wattson settings, so to do that you still need Holmes.

On the other hand, in all the time since my original review, Holmes has only managed to scrabble out a bug-fix release, version 1.05, which adds no new features. "Sit back and take the money".

Wattson remains a nice, but expensive, display of instantaneous consumption. But it could be so much more with some development on the software. It's sad that the developer can't be bothered!

I only use the Holmes software now to show the generated against used bar graphs and for a approx costing.I have used Powomneter a lot recently.Actually its running 24/7.

With 2 screens, one set to weekly and one to 6hrs I have been able to see what appliances etc influence my power usage. It also showed a couple of issues Im having, one with my fridge that usually uses about 300w but on some startups goes to 3000watts for a short time. This was only happening at night.This will be investigated, 2nd one with a water pump that was leaking down thru the controller and switching on when I wasnt aware of it. (Controller changed) So it has other uses

Acurracy is about 60watts out but I can live with that as I know IF I really need to go to that level (not)Same for the solar input

bazzle wrote:Errr no, pc runs 24/7, winds down to power save. Some things Im not too bothered about. It has other uses too. Power when on is 18w

Bazzle

That's an impressive PC. Most use >=150W even when power saving. An Intel Core 2 Duo (just the processor, no disk drives etc.) pulls about 80W at idle, which means that even after power saving everything else - monitor, disks, fans etc. - out of the equation it's very hard to get below about 100W for the machine. And I've found that many pieces of software, especially those that make regular writes to the disk (like monitoring software, though I've not checked Holmes or Powometer) will effectively remove the ability to power save a disk.

I had the same issue some time back with a requirement to run a PC 24/7 for monitoring, and ended up with a NetTop (actually an Ion) with a solid state disk and no monitor. That system runs on the smell of an oily rag! The other options were an eeePC (not quite powerful enough) or a laptop (more money to do the same job).

bazzle wrote:Not wanting to go off topic but its an ATom and when it takes its charge.

Bazzzle

You're not off topic. The PC used to run software to investigate/monitor/record the output of the Wattson is a legitimate part of the discussion, especially if it's running 24/7.

The Ion that I am using also is Atom powered, being an ASRock Ion with an Atom 330 processor. It is dedicated to monitoring, storing information from the PV system, the farm irrigation system and also the weather station, the last two functions being the reason for it's existence whilst the PV data is nice to have. It runs without a monitor, I simply make a remote desktop connection to it when required which means that it does not need to be on my desk. But I've still found that by the time the ethernet switch, and in my case the wireless bridge and satellite, plus a UPS are powered up, the total consumption starts to mount. Not like an electric heater, but certainly to light bulb levels! The Ion itself is indeed a remarkably low powered device though.

I will have to try running Powometer on it and see what it looks like!

I found the Envi's ability to store lots of data a winner, it does lack the clarity that it has when connected to a PC and logging continuously but this is off set by the fact I dont run the PC which is obviously for most people highly counter productive.

Laptops are the go.

Did anyone consider the cost as a factor in their purchase? (of the wattson)

The Wattson is twice the price of most of the others (I really like the effergy and its my pick)for the sake of it here's how I came to not buying the Wattson$100 more expensive = ~500KWhr more that it would need to save me before it paid for itself.Assuming you take notice of the colour of the glow and race around turning off things in the house to "Combat" the unreal use of power. -like turning off the fridges, laptops, tv's heaven forbid making a coffee!aside from the fact we'd be divorced, it would need to save us an additional 500Kwhrs over any of the other devices

The unfortunate thing here is in fact I now have three such inferior devices which in total cost more and in the case of the ENVI have the same problem with poor software available.

Now I'm waiting for the next generation!

I envisage a device very similar that talks to the grid and changes its colour based on the electricity price as well --hang on if the software was there perhaps the wattson could do that anyway

-assuming TOU as it is now there is no reason it couldnt be programmed to turn red at say 5KW on the night rate and 1KW on the day rate

Rest assured we are the pioneers of this stuff and as time goes on there will be a demand for it, next will be an iphone app that talks to googlepower (if you log continuously) and tells you when the nanny is running the dishwasher during the day. (currently strictly forbidden)